Cyclonic type fuel burner

ABSTRACT

The invention is directed to a fuel burner for combustible material, the burner having a horizontally disposed, circular combustion chamber into which all types of dry or semi-dry combustible material, including waste material, which has been reduced to small particulate size, or various types of combustible luquid wastes, together with air for supporting combustion, are injected tangentially into the combustion chamber. The invention is also directed to the method of burning combustible material and to the method of providing heat energy.

United States Patent 1 Lutes et al.

[ Dec. 11, 1973 CYCLONIC TYPE FUEL BURNER [75] Inventors: Kenneth V.Lutes, Escondido; James E. Lander, San Clemente; Vincent J. Shanahan,Escondido; Richard G. Mills, Solana Beach, all of Calif.

[73] Assignee: Macmillan Bloedel Ltd.

[22] Filed: June 14, 1971 [21] Appl. No.: 152,541

[52] US. Cl 110/8 R, 110/28 F [51] Int. Cl. F23g 5/06 [58] Field ofSearch 110/8 C, 8 R, 28 F; 431/173 [56] References Cited UNITED STATESPATENTS 3,199,476 8/1965 Nettel 110/28 F 2,387,005 10/1945 Boedecker..110/18 R 2,881,720 4/1959 Lotz 110/28 F 1,618,808 2/1927 Burg 431/1732,800,091 7/1957. Lutz 110/28 F 2,592,491 4/1952 Toepel 110/8 C3,500,775 3/1970 Hubbard 110/8 R 2,769,411 11/1956 Simmons 431/173Primary Examiner-Kenneth W. Sprague Assistant ExaminerJames C. YeungAtt0rneyCarl K. Brown and Neil F. Martin [57] ABSTRACT The invention isdirected to a fuel burner for combustible material, the burner having ahorizontally disposed, circular combustion chamber into which all typesof dry or semi-dry combustible material, including waste material, whichhas been reduced to small particulate size, or various types ofcombustible luquid wastes, together with air for supporting combustion,are injected tangentially into the combustion chamber. The invention isalso directed to the method of burning combustible material and to themethod of providing heat energy.

10 Claims, 8 Drawing Figures PAIENTEBUEC n ma (777,678 SHEET 1m 4 a9 94a7 96 L /56 3 76 FIG. I

% KENNETH V. LUTES JAMES E. LANDER L BY RICHARD e. MILLS M H1 ATTORNEY.

INVENTORS.

VINCENT J. SHANAHAN akntsTa 81113 2 CF 4 PAIENIEDDEB 11 I975 JAMES E.LA-NDER VINCENT J. SHA NAHAN BY wcHARo e. MILLS W ATTORNEY.

PAIENIEBHEI: n ma 3777.678

I NVENTORS KENNETH V. LUTES JAMES E. LANDER VINCENT J. SHANAHAN R/cHAFwG. MILLS BY {Mm #1 1 ATTORNEY.

PAIENIED DEC 1 1 I975 SHEET 4 LF INVENTORS KENNETH V LUTES JAMES E.LANDER VINCENT J. SHANAHAH BY RICHARD G. MILLS WWI m HZ/YafiMi/MMTTORNEX1 CYCLIONIC TYPE FUEL BURNER BACKGROUND OF THE INVENTION tion chamberadjacent that end wall. In the present invention, the combustiblematerial can enter the combustion chamber tangentially, and the air isdistributed to that chamber at a plurality of areas along the length ofthe chamber. Also, the air pressure, velocity and volume can be variedas desired in those areas.

SUMMARY OF THE INVENTION The invention relates to a cyclonic type fuelburner in which the combustible materials aforesaid are injectedtangentially into a horizontally disposed combustion chamber to impartwhirling movement to the combustible material. The whirling movement isaugmented by injecting air tangentially into the combustion chamber atdifferent areas throughout the length of the combustion chamber, theinjected air also providing the air for supporting combustion. The airpressure, velocity and volume in the various areas along the combustionchamber can be varied to thereby effect the desirable flame lengths.

The construction of the burner is such that the refractory walls thereofare heated to such high degree that the combustible material is heatedto kindling temperature whereby, after starting the burner, the pilotflame can be extinguished.

The invention is directed also to a burner of the type which can be usedin multiple for preheating the wall, for example of a tepee-typeincinerator.

Other features and the advantages of the present invention will beapparent from the following description, reference being made to theaccompanying drawings wherein a preferred embodiment of the invention isillustrated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of thecyclonic type fuel burner and the blower for injecting air into thecombustion chamber of the burner;

FIG. 2 is a side view of the apparatus shown in FIG. 1;

FIG. 3 is a sectional view of the burner taken along line 33 of FIG. 1,but showing the same on a larger scale, the view also showing the blowerin elevation;

FIGS. 4 and 5 are sectional views taken along lines 4-4 and 5-5,respectively, of FIG. 3;

FIG. 6 is a fragmentary sectional view taken along line 66 of FIG. 1;

FIG. 7 is a sectional view of an incinerator of the tepee type showingtwo of the present burners in posi tion; and

FIG. 8 is a sectional view taken along line 8-8 of FIG. 7. v

DESCRIPTION OF THE PREFERRED EMBODIMENT The cyclonic burner 20 comprisesa relatively elongated, circular, and preferably cylindrical wall 22which is horizontally disposed, a front end wall 24 and a rear end wall26. These walls are formed of desirable refractory material and form acombustion chamber 28. As seen in FIG. 3, the front end wall is providedwith an opening 30 for receiving air and a pilot burner 32. Thecylindrical wall, as seen in FIG. 4, is provided with a tangentiallydisposed opening 34 which receives a metal tube 36. The rear end wall 26is provided with a centrally disposed opening 38 that forms the outletfor the combustion chamber 28.

A sheet metal wall 40 encircles the refractory wall 22. A ring 42 ofsheet metal surrounds the front wall 24 and a ring of sheet metal 44surrounds the rear wall 26. Rings 42 and 44 are fixed, respectively, tothe front and rear ends of the encircling wall 40. The cylindrical wall22 and the encircling wall 40, as shown in FIGS. 3 and 5, are providedwith a plurality of openings 46 that extend through the wall 22. Theseopenings 46 are tangentially disposed along the length of that wall 22for directing air tangentially into the combustion chamber along thelength thereof.

A plurality of heat insulating sections 48, 50 and 52 surround thecombustion chamber 28. Sections 48, 50 and 52 include, respectively,cylindrical heat insulating walls 54, 56 and 58 that are spaced radiallyfrom the combustion chamber 28; these sections also include,respectively, surrounding sheet metal walls 62, 64 and 66. A ring 68 ofsheet metal closely embraces the sheet metal wall 40 and is disposedbetween sections 48 and 50, and a like ring closely embraces the sheetmetal wall 40 and is disposed between sections 50 and 52. Sheet metalwalls 62 and 64 and ring 68 are suitably sealed with one another, andsheet metal walls 64 and 66 and ring 70 are sealed with one another.

An insulating wall 72 covers the front refractory wall 24 and a sheetmetal wall 74 covers thelinsulating wall 72 and is sealed to the frontend of the circular sheet metal wall 62. A sheet metal wall 76 coversthe rear wall 26 of the combustion chamber and is sealed to the rear endof the sheet metal wall 66. Thus the area between the sheet metal 40 andring 42 that surrounds the combustion chamber, the heat insulation 48,the sheet metal cover 74, and the ring 68 form a cylindrical air chamber78. The area between the sheet metal 40, the insulation and the rings 68and 70 form a cylindrical air chamber 80. The area between the sheetmetal 40, the rings 44, the insulation 58 and the rear end cover 76 forma cylindrical air chamber 82.

Air chambers 78, 80 and 82 are onnected, respectively, to an air pipe 84by manifold air pipes, each of which includes two sections 86-87, 88-89and 90-91, respectively. These pipes are provided, respectively.

' with air flow control valves 96, 94 and 92 (see FIGS.

' pipes 84, 86, 88 and 90. By adjusting the valves the air pressure,velocity and volume can be controlled in the air chambers 78, 80 and 82resulting in the admission of desired different pressures,velocity andvolumes of air along, the interior of the combustion chamber. In thism'a'nn'er, the-length of the flame can be controlled and combustion canbe optimized. If desirable, the flame can be extended variable lengthsbeyond the combustion chamber 28; or when the burner is employed as anair heater, the air flows to the combustion chambers can be varied sothat the flame is confined within the combustion chamber.

The combustible material to be burned is injected by any of the wellknown force-feeding mechanisms, for example, such as that shown in theaformentioned Patent to Burden, .lr., et al., No. 3,453,976 or thePatent to Burden, Jr., No. 3,472,185 However, in the present apparatus,the material to be burned enters tangentially into the combustionchamber through the tube 36 that is disposed tangentially with respectto the interior circular wall 22 of the combustion chamber.

Thus it is apparent from the foregoing that by tangentially injectingthe combustible material, which is to be burned in the combustionchamber 28, whirling movement will be imparted to the material as it isbeing burned and the whirling movement is augmented continuouslythroughout the length of the combustion chamber by imparting tangentialmovement to the air through the outlets of the tangentially disposedopenings 46 in the circular wall 22. This air functions both as primarycombustion air and as air for conveying combustible material through thecombustion chamher. The control of this air determines retention time ofthe combustible material in the combustion zone of the combustionchamber.

It has been discovered that these burners are of particular value forpreheating an incinerator device such as, for example, the tepee orwigwam burner shown in FIGS. 7 and 8. The tepee type incinerator 102disclosed herein includes the frustoconically shaped sheet metal skin104, the top 106 of which is open to atmosphere.

The periphery of the pile of combustible material 118 is spaced inwardlyof the incinerator skin 104 to provide a space 120 surrounding the pile.A plurality of burners 20, preferably three, are disposed, as shown inFIG. 8, in positions for directing hot air, emanating therefromtangentially, into this space 120. The air flow regulating valves 92, 94and 96 are adjusted so that flames emanating from the burner do notextend to the pile and are contained within the burners.

The base of the incinerator 102 carries the usual perforated air chamber122 above which the combustible material 118 is piled. Air forsupporting combustion is delivered to the chamber 122 under pressurethrough a pipe 124.

It has been found that all tepee type incinerators emit trememdous andobjectionable volumes of heavy and dense smoke during periods when thetemperature of the steel skin of the tepee is cold, such as at the timethe pile of waste material is first lit or fired, or at any time whilethe tepee is in operation and when the amount of waste material that isbeing fed into the tepee is not sufficient to maintain a degree oftemperature sufficiently high to maintain the skin of the tepeeuniformly hot. It has been found that the temperature of the steel skinmust be maintained at approximately 400 F. around the lowerthree-fourths of the structure and at approximately 750 F. at the top orcrown of the structure in order to promote good combustion within thestructure and to burn the smoke generated by'the burning pile of wastematerial.

The cyclonic type combustible material burner, as herein illustrated,provides an excellent burner for the method of preheating the steel skinof the tepee type incinerator; and by the use of regulating controls 92,94 and 96, a method of maintaining the skin temperature at requiredlevels throughout the entire operating period of the tepee incineratoris achieved. This is particularly true when a plurality of burners, suchas shown in FIG. 8, are employed.

It will be understood by those skilled in the art that theherein-disclosed waste fuel burner can be applied in boilers as overfirefor smoke elimination and as a prime B.T.U. source for boilers, dryers,kilns, etc.

It is to be observed, particularly from FIG. 3, that the outlet 38 ofthe rear refractory wall 26 of the combustion chamber 22 is restrictedto provide a choke at the exit of the combustion chamber. It has beenfound that by choking or restricting the outlet of the combustion'chamber, the refractory walls can be heated to such high value that thecombustible material is raised to its kindling temperature. By thisphenomenon there is no need for maintaining the flow of extraneous fuelsuch as gas or oil that is used for starting the operation of theburner. From the foregoing, the burner uses only combustible wastematerial after the burner becomes operative, resulting in minimizing therequirement of extraneous fuels. Thus the burner, after being started,uses only waste and converts this waste into useful energy.

lt will be understood by those skilled in the art that standard controlinstruments are employed for controlling the burner, such asthermostats, etc., when the burner or burners are rendered operative andinopera' tive for maintaining temperature between limits. Such standardcontrol instruments also control the timing of blowers, ignition, etc.

The word shredded as used herein includes sawdust, or dry or semi-drycombustible waste which has been pulverized, ground, milled or otherwisereduced to small particulate sizes so as to be capable of beingsuspended in a stream of air.

Thus, from the foregoing it is apparent that by virture of the presentinvention, there has been provided a burner for combustible material,such as sawdust, waste products, etc., in which air for supportingcombustion is supplied substantially throughout the length of ahorizontally disposed combustion chamber. This air in addition to itsfunction of supporting combustion, imparts whirling movement to thecombustible material, which was injected tangentially into thecombustion chamber, throughout the horizontal length of the chamber.

Also, by providing separate air feeding chambers through the length ofthe combustion chamber, by suitable regulatable valves, the length ofthe flame generated in the chamber can be varied as desired. Thus, forexample, if the burner is employed as an air heater, the flame can becontained within the chamber.

Too, the burner or burners can be utilized as preheaters of combustiblematerial that is to be incinerated, the effect of which is to minimizethe generation of unburned combustible materials and unburnedcombustible gases.

Having described our invention, we claim:

1. Apparatus for burning combustible material, said apparatuscomprising:

A. a substantially horizontally disposed, circular combustion chamberformed by:

l. a refractory front wall,

2. a refractory rear wall having an outlet opening,

3. a substantially horziontally disposed, circular wall formed ofrefractory material, said latter wall being jointed with the front andrear walls, said material of the substantially circular wall having aplurality of tangentially disposed openings therethrough spaced alongthe length thereof, said circular wall having a separate opening thereindisposed for admitting combustible material tangentially into thecombustion chamber;

B. means substantially surrounding the circular refractory material,said meansbeing spaced from the circular refractory material providingan air space in open communication with the tangentially disposedopening in the circular refractory material;

C. means for injecting combustible material through said combustiblematerial opening;

D. means for injecting air into the space lying between the refractorymaterial and the first mentioned means.

2. Apparatus as defined in claim 1, characterized in that the firstmentioned means includes heat insulation substantially surrounding therefractory material.

3. Apparatus as defined in claim 2, characterized to include:

E. means for dividing the circular air space into a plurality oflongitudinally disposed air chambers, each in open communication withthe tangentially disposed opening in the insulating material.

4. Apparatus as defined in claim 1, characterized in that the openingfor combustible material is disposed in the substantially circular walladjacent the front wall.

5. The steps in the method of burning waste combustible material in acombustion chamber formed of a horizontally disposed, substantiallycircular wall and a rear wall, the circular wall having an opening andan air chamber disposed longitudinally of the combustion chamber, whichsteps comprise:

A. forcing combustible material under pressure through an opening in thecircular wall of the chamber adjacent the front wall of the chamber,which opening is tangentially disposed relative to said circular wall tocause the combustible material to whirl within the combustion chamber;

B. igniting the combustible material adjacent the opening;

C. supplying the necessary air to said combustion chamber throughseparate openings through said circular wall from the longitudinallydisposed air chamber for supporting combustion of the combustiblematerial and augmenting the whirling of the combustible material byimparting tangential movement of the air that enters through thelongitudinally disposed air chamber and separate along the periphery ofthe combustion chamber;

D. exhausting burned gases through the opening in the rear wall of thecombustion chamber.

6. The steps in the method as defined in claim 5 characterized toinclude the step of regulating the length of the flame which is producedby the burning particles, which step comprises:

E. varying the relative quantities of air flowing to the longitudinallydisposed air supplying chambers to retain the flame within the confinesof said combustion chamber.

7. The steps in the method of burning waste combustible material, whichsteps comprise:

A. placing the combustible material in an area that is spaced from andsurrounded by a wall;

B. preheating the wall by injecting a plurality of streams of heated airfrom a plurality of burners tangentially into the area between thecombustible material and the wall;

C. regulating the burners to prevent flames from flowing into the area;

D. thereafter regulating the burners to heat the combustible material toa kindling temperature, and

E. supplying air from an air outlet on the longitudinal center of thevolume enclosed by the Wall.

8. The steps as defined in claim 7, characterized in that the wall isthe steel skin of the lower section of a tepee type incinerator and thatthe temperature of the skin is preheated to approximately 400F. prior toheating the combustible material to a kindling temperature.

9. The steps as defined in claim 7, characterized in that the wall isthe steel skin of the lower section of a teepee type incinerator andthat the temperature of the skin, after once being preheated toapproximately 400F., is maintained at that temperature.

10. The steps as defined in claim 7, characterized in that the wall isthe steel skin of a teepee type incinerator and that the temperature ofthe lower section of the skin is preheated to approximately 400F. priorto heating the combustible material and after once being preheated toapproximately 400F., is maintained at that temperature and the crown ofthe skin is maintained at approximately 750F.

1. Apparatus for burning combustible material, said apparatuscomprising: A. a substantially horizontally disposed, circularcombustion chamber formed by:
 1. a refractory front wall,
 2. arefractory rear wall having an outlet opening,
 3. a substantiallyhorziontally disposed, circular wall formed of refractory material, saidlatter wall being jointed with the front and rear walls, said materialof the substantially circular wall having a plurality of tangentiallydisposed openings therethrough spaced along the length thereof, saidcircular wall having a separate opening therein disposed for admittingcombustible material tangentially into the combustion chamber; B. meanssubstantially surrounding the circular refractory material, said meansbeing spaced from the circular refractory material providing an airspace in open communication with the tangentially disposed opening inthe circular refractory material; C. means for injecting combustiblematerial through said combustible material opening; D. means forinjecting air into the space lying between the refractory material andthe first mentioned means.
 2. a refractory rear wall having an outletopening,
 2. Apparatus as defined in claim 1, characterized in that thefirst mentioned means includes heat insulation substantially surroundingthe refractory material.
 3. Apparatus as defined in claim 2,characterized to include: E. means for dividing the circular air spaceinto a plurality of longitudinally disposed air chambers, each in opencommunication with the tangentially disposed opening in the insulatingmaterial.
 3. a substantially horziontally disposed, circular wall formedof refractory material, said latter wall being jointed with the frontand rear walls, said material of the substantially circular wall havinga plurality of tangentially disposed openings therethrough spaced alongthe length thereof, said circular wall having a separate opening thereindisposed for admitting combustible material tangentially into thecombustion chamber; B. means substantially surrounding the circularrefractory material, said means being spaced from the circularrefractory material providing an air space in open communication withthe tangentially disposed opening in the circular refractory material;C. means for injecting combustible material through said combustiblematerial opening; D. means for injecting air into the space lyingbetween the refractory material and the first mentioned means. 4.Apparatus as defined in claim 1, characterized in that the opening forcombustiblE material is disposed in the substantially circular walladjacent the front wall.
 5. The steps in the method of burning wastecombustible material in a combustion chamber formed of a horizontallydisposed, substantially circular wall and a rear wall, the circular wallhaving an opening and an air chamber disposed longitudinally of thecombustion chamber, which steps comprise: A. forcing combustiblematerial under pressure through an opening in the circular wall of thechamber adjacent the front wall of the chamber, which opening istangentially disposed relative to said circular wall to cause thecombustible material to whirl within the combustion chamber; B. ignitingthe combustible material adjacent the opening; C. supplying thenecessary air to said combustion chamber through separate openingsthrough said circular wall from the longitudinally disposed air chamberfor supporting combustion of the combustible material and augmenting thewhirling of the combustible material by imparting tangential movement ofthe air that enters through the longitudinally disposed air chamber andseparate along the periphery of the combustion chamber; D. exhaustingburned gases through the opening in the rear wall of the combustionchamber.
 6. The steps in the method as defined in claim 5 characterizedto include the step of regulating the length of the flame which isproduced by the burning particles, which step comprises: E. varying therelative quantities of air flowing to the longitudinally disposed airsupplying chambers to retain the flame within the confines of saidcombustion chamber.
 7. The steps in the method of burning wastecombustible material, which steps comprise: A. placing the combustiblematerial in an area that is spaced from and surrounded by a wall; B.preheating the wall by injecting a plurality of streams of heated airfrom a plurality of burners tangentially into the area between thecombustible material and the wall; C. regulating the burners to preventflames from flowing into the area; D. thereafter regulating the burnersto heat the combustible material to a kindling temperature, and E.supplying air from an air outlet on the longitudinal center of thevolume enclosed by the wall.
 8. The steps as defined in claim 7,characterized in that the wall is the steel skin of the lower section ofa tepee type incinerator and that the temperature of the skin ispreheated to approximately 400*F. prior to heating the combustiblematerial to a kindling temperature.
 9. The steps as defined in claim 7,characterized in that the wall is the steel skin of the lower section ofa teepee type incinerator and that the temperature of the skin, afteronce being preheated to approximately 400*F., is maintained at thattemperature.
 10. The steps as defined in claim 7, characterized in thatthe wall is the steel skin of a teepee type incinerator and that thetemperature of the lower section of the skin is preheated toapproximately 400*F. prior to heating the combustible material and afteronce being preheated to approximately 400* F., is maintained at thattemperature and the crown of the skin is maintained at approximately750*F.